Shower Drain Question: internal ABS pipe coupler?

[AZRedhawk44]

I'm still struggling with my shower rebuild project, and I'm stuck.

I've demolished and removed the old shower pan and vinyl liner.  There is a 3-piece shower drain flange assembly, ABS plastic, made by Plumbing Products Company, Inc.  It is a 2" drain adapter that clamps around your vinyl pan liner with 3 bolts, then the upper assembly has an integrated proprietary drain cover.  Our drain is corroded as are the threaded receptacles that retain the drain.  The drain is also a 3" rather uninspiring flimsy thing even when new.  If I'm re-tiling the whole thing, I want it to look nice.

Home Depot, Lowes and Ace don't carry this brand.  All the drain flange assemblies they carry are 4-bolt pattern and won't mate up with this 3-bolt one that is currently mated to my drain line in my foundation.

So I've been looking into all manner of drain conversions or alternate systems.  Which brings me into the world of Schluter, FloFX and all the other high tech impermeable membranes out there.  I end up learning about foam shower pans, which would save me from having to do a mudpack shower pan.  And I can also have a more cosmetically pleasing shower drain in the process.

But I'm stuck!

The puzzle is how to remove the bottom part of the 3-piece shower drain flange.  It's ABS-cemented to my drain pipe, and the P-trap's water line is only 5" below concrete level.  I need to re-create a 2" stub-out somehow.  In order to do that, I need to use an inside pipe cutter to remove the lower flange, but leave enough material to use a 2" to 2" coupler to raise the drain pipe back up out of the ground.  Most couplers are external couplers, and it's more than likely that the drain flange is bonded to the exterior of the 2" pipe its entire length.  As such I won't be able to attach an external coupler.

Have any of you come across an internal 2" ABS pipe coupler?  That would solve my problem really well.

[cordex]

Something like this?
https://www.amazon.com/Magic-Plastics-0302-20-Insider-Connector/dp/B00GM45DSM

I used Schluter membrane for most of my tile (decoupling membrane on the floor and regular membrane on the walls), but I wouldn’t personally use any of the foam shower pans. Way too many examples of premature failure resulting in leaks and serious damage outside of the shower even before the tiles start popping off.

[Bogie]

Do I need to fire up the lathe?
 
Aluminum is easy.. Delrin would take longer.

[AZRedhawk44]

Something like this?
https://www.amazon.com/Magic-Plastics-0302-20-Insider-Connector/dp/B00GM45DSM

I used Schluter membrane for most of my tile (decoupling membrane on the floor and regular membrane on the walls), but I wouldn’t personally use any of the foam shower pans. Way too many examples of premature failure resulting in leaks and serious damage outside of the shower even before the tiles start popping off.

Exactly like that, but not PVC.  Gotta be ABS.

I'm going to Grainger tomorrow to see what they have.  Supposedly I should be able to get away with either a 2" ABS sched 40 extender, or M-to-M coupler.  They exist, but aren't popular because they reduce the diameter of the internal pipe.  Extenders are F-to-M connectors.  Both have the same drawback, but they do exist.

As for the foam pan concerns, my understanding is that most of the problems stem from improper leveling or lack of leveling of the subsurface.  Assume your foundation is level and you're in for a bad time.  Any little bit of flex, including in your drain collar, and you're cracking your grout and loosening your tile and the damage is coming.  As long as you don't cut corners and use a self leveling underlay, you should be good.

I'm still on the fence when it comes to mudpack vs foam tray.  This drain issue will probably decide it for me.  If I can't bring the drain down close enough to the foundation with the coupler situation then I'll end up having to do a mudpack anyways, and I'll put membrane over that.

[K Frame]

OK, I think I may have found something along the lines of what you're looking for here:

https://www.plumbingsupply.com/absplasticfittings.html

Down in the 2" section, it's called a 2"x3" multi use coupling.